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An attachment of a particle on a bubble is a very complex process due to the surface chemistry of bubbles and particles, and hence it is difficult to describe the bubble–particle attachment mechanism from first principles. This paper focuses on better understanding of the bubble–particle attachment mechanism by predicting induction time from first principles for the glass beads–dodecyl amine hydrochloride (DAH) system. The induction time for the bubble–particle attachment was determined using an optically based attachment timer. The zeta potentials of bubbles and glass particles were measured by the microelectrophoresis method. The contact angle between a bubble and a particle was obtained using atomic force microscopy. In these calculations, the overall disjoining pressure and the overall energy of bubble–particle interactions comprised a sum of the DLVO and non-DLVO contributions. The overall energy of interactions was used to determine the critical film thickness, while the overall disjoining pressure was employed to estimate the wetting film drainage time using the theoretical models. By comparing experimental data and theoretical models for drainage of wetting films, it was found that the attachment of glass particles to air bubbles in the presence of DAH is accelerated due to the mobility of the air–water interface (of the wetting films), which has incorrectly been assumed as rigid (fully immobile) in the classical Stefan–Reynolds theory. [ABSTRACT FROM AUTHOR]

Typically, it is difficult to analyze and design a micro/nanofluid system, and the design process cannot follow the traditional law of hydrodynamics. The boundary condition is very important in the applications of a micro/nanofluid system. The existence of boundary slip can reduce the hydrodynamic resistance and enhance fluid flow. How to accurately determine the dynamic boundary conditions is increasingly concerned by researchers. Atomic force microscope (AFM) is proven to be the most advanced experimental instrument for studying the characteristics of the surface and the interaction interface. Most studies on the application of atomic force microscopy to the measurement of the boundary slip do not describe a systematic standard process, leading to many differences in the measurement results. In this paper, a standard process of measuring slip on smooth and flat surfaces is developed, including the data processing methods that minimize the interference factors in the original data as well as simplify the data expression. Thus, the boundary slip can be obtained more easily and accurately. [ABSTRACT FROM AUTHOR]

This review critically summarizes the recent advances of the microcantilever-based force sensors for atomic force microscope (AFM) applications. They are one the most common mechanical spring–mass systems and are extremely sensitive to changes in the resonant frequency, thus finding numerous applications especially for molecular sensing. Specifically, we comment on the latest progress in research on the deflection detection systems, fabrication, coating and functionalization of the microcantilevers and their application as bio- and chemical sensors. A trend on the recent breakthroughs on the study of biological samples using high-speed atomic force microscope is also reported in this review. [ABSTRACT FROM AUTHOR]

Surface nanobubbles at hydrophobic interfaces now attract much attention in various fields but their role in wetting-related phenomena is still unclear. Herein, we report the effect of a preliminary contact of "hot" solids with cold water previously proposed for generation of surface nanobubbles, on wettability of compact materials and flotation of particulate galena (PbS), sphalerite (ZnS), and Pb-Zn sulfide ore. Atomic force microscopy was applied to visualize the nanobubbles at galena crystals heated in air and contacted with cold water; X-ray photoelectron spectroscopy was used to characterize the surface composition of minerals. Contact angles measured with the sessile drop of cold water were found to increase when enhancing the support temperature from 0 to 80 °C for sphalerite and silica, and to pass a maximum at 40–60 °C for galena and pyrite (FeS2) probably due to oxidation of sulfides. The temperature pretreatment depressed the recovery of sulfides in collectorless schemes and improved the potassium butyl xanthate-assisted flotation both for single minerals and Gorevskoye Pb-Zn ore. The results suggest that the surface nanobubbles prepared using the temperature difference promote flotation if minerals are rather hydrophobic and insignificantly oxidized, so the addition of collector and activator (for sphalerite) is necessary. [ABSTRACT FROM AUTHOR]